标题： 从低于阈值到高于阈值的激光器中的偏振特性在宽区垂直腔面发射激光器中的研究 显示英文标题

标题： Polarization properties in the transition from below to above lasing threshold in broad-area vertical-cavity surface-emitting lasers

摘要： 对于宽区垂直腔面发射激光器（VCSELs）的高发散度辐射，当泵浦速率接近激光阈值时，偏振方向会发生高达90度的旋转。 低于阈值时，偏振方向与横向波矢方向平行，并由构成腔镜的布喇格反射器的透射特性决定。 相反，在接近阈值和高于阈值的辐射中，反射器的反射特性影响更大，且偏振方向主要与横向波矢方向垂直。 展示了两种定性不同的偏振转变类型：一种是突然转变，在转变点光的偏振消失；另一种是平滑转变，在转变过程中偏振显著不为零。 显示英文摘要

摘要： For highly divergent emission of broad-area vertical-cavity surface-emitting lasers (VCSELs) a rotation of the polarization direction by up to 90 degrees occurs when the pump rate approaches the lasing threshold. Well below threshold the polarization is parallel to the direction of the transverse wave vector and is determined by the transmissive properties of the Bragg reflectors that form the cavity mirrors. In contrast, near-threshold and above-threshold emission is more affected by the reflective properties of the reflectors and is predominantly perpendicular to the direction of transverse wave vectors. Two qualitatively different types of polarization transition are demonstrated: an abrupt transition, where the light polarization vanishes at the point of the transition, and a smooth one, where it is significantly nonzero during the transition.